Steady Secondary Flow in a Plane Turbulent Free Jet

Abstract

Asymptotic methods are applied to study a plane turbulent jet of a viscous incompressible fluid flowing out through a narrow slot into a space filled with a fluid. The complete Navier—Stokes equations are considered. The characteristic Reynolds number is assumed to be large, while the jet thickness is small. In analyzing the problem the method of many scales is used, which makes it possible to determine and investigate a steady secondary flow within the turbulent jet. The secondary steady solutions are analytically obtained for the normal and longitudinal velocity components and the pressure. It is shown that the self-induced fluid outflow of the jet core toward the jet periphery is the main secondary flow ensuring the supply of the kinetic energy from a maximum velocity zone into the turbulence production zone. The solutions obtained are in good agreement with the available experimental data.